1. Field of the Invention
The present invention relates generally to a fan cylinder to be installed to the upper side of a cooling tower, and more particularly to a fan cylinder for a cooling tower, which is configured so as to prevent the air discharged from the cooling tower from flowing back into the cooling tower, as well as, to achieve a reduction in transmission of noise generated during operation of a cooling fan.
2. Description of the Related Art
As is well known, cooling towers are installed in a freezer, heat exchangers, or air conditioning equipments in order to absorb heat from high temperature cooling water used in heat exchange, and to continuously supply with low temperature cooling water.
Typically, a cooling tower is constructed so that it forcibly introduces substantially dry low temperature outside air thereinto using a cooling fan, and heat-exchanges between the inflow air and cooling water, and then discharges resulting hot and humid air outwardly. The cooling fan of the cooling tower is provided at the outer side thereof with a fan cylinder for effective maintenance of air streams discharged outwardly from the cooling fan.
Considering one exemplary structure of the cooling tower, as shown in FIG. 1, the cooling fan, designated as reference numeral 21, is installed inside the fan cylinder, designated as reference numeral 20, having an air-discharge opening formed therein. With such a configuration, substantially dry low temperature outside air is introduced into an air-inflow part formed in a side of the cooling tower, and heat-exchanged with cooling water, and then discharged to the outside through the above mentioned air-discharge opening.
The fan cylinder 20 having the air-discharge opening has been formed into various shapes, and is classified, according to the shape thereof, into a fan cylinder consisting of only a linear portion mounted therein with a cooling fan, a fan cylinder further having an inlet portion in addition to the linear portion, and a fan cylinder further having an extension portion in addition to the linear portion and the inlet portion.
These various shapes of the fan cylinder 20 are shown in FIGS. 2A to 2C, respectively. The fan cylinder 20 consisting of only the linear portion, as shown in FIG. 2A, has a height slightly higher than that of the cooling fan 21 mounted therein. Another fan cylinder, as shown in FIG. 2B, is additionally formed at the lower side of the linear portion thereof with an inlet portion, which has an inner diameter increasing downwardly, thereby serving to reduce inlet resistivity of the air introducing into the cooling fan 21. Yet another fan cylinder, as shown in FIG. 2C, is additionally formed at the upper side of the linear portion thereof with an extension portion, which has an inner diameter increasing upwardly, thereby serving to reduce discharge resistivity of the air to be discharged from the cooling fan 21.
Specially, in case of a cross-flow type cooling tower, there is an essential disadvantage in that, since the air-inflow part located in the side of the cooling tower is positioned so close to the air-discharge opening formed at the upper side of the cooling tower, the hot and humid air discharged through the air-discharge opening after completing the heat exchange within the cooling tower, often flows back into the air-inflow part. Because such an inflow of the hot and humid air into the cooling tower is an important reason of a deterioration in capability of the cooling tower, it is insufficient in heat exchange between the inflow air passed through a filler material of the cooling tower and the high temperature cooling water sprayed from the upper side of the cooling tower, and thus cause deteriorative performance of a cooling tower.
Additionally, the fan cylinder of the prior art has in a problem that noise generated from the cooling fan was directly transmitted to the peripheral environment, and cause noise pollution.